Buoyage SystemsSystemsA buoyage system consists of fixed, floating, lighted, and unlightedATONs. These aids are used to mark waterways. There are twobuoyage systems that are in use throughout the world-the lateralsystem and the cardinal system.Lateral SystemIn the lateral system, aids are placed to mark the sides of a navigablechannel. They also mark junctions and bifurcations, indicate the safeside on which to pass hazards, and mark the general safe centerline ofwide bodies of water.In U.S. waters, a vessel returning from seaward and proceeding towardthe head of navigation is generally considered as moving southerly alongthe Atlantic Coast, westerly along the Gulf Coast, and northerly alongthe Pacific Coast. This is what is known as the "conventional direction"of buoyage. Virtually all U.S. lateral marks are located in what isknown as IALA region B and follow the traditional "red right returning"rule.Cardinal System In the cardinal system, aids generally mark the geographic relationshipto the aid of a hazard in terms of 90-degree quadrants centered on thecardinal directions of north, east, south, and west. The cardinal systemis not widely used in the United States and will not be discussed in thistext. For more information on the cardinal system, consult Dutton'sNavigation and Pilotingor Bowditch.4-27